Technological advances in various disciplines such as computer vision, ranging sensors, wireless communications and estimation and detection algorithms have made autonomous vehicles a reality. From automated flying drones to automobiles, these vehicles have the ability to make decisions and perform almost any maneuver without any human assistance. Such maneuvering can be safely performed, for example, on public roadways with traffic present and includes emergency stopping, steering and turning, navigating, lateral and garage parking. Sensor data and other information is collected and processed in order to facilitate lane keeping, traffic signs recognition and awareness, object tracking in vehicle's operating range (pedestrians or other vehicles), etc. and then used to determine accordingly the vehicle's desired trajectory.
However, there are still many operations of autonomous vehicles which are difficult to perform in an automated fashion. For example, platoon motion control has been a problem of interest for the control engineering community for about fifty years and still persists. The platoon motion control problem is easy to solve (using standard design methods) provided that each vehicle in the platoon has instant access at all times at the relative coordinates and at the instantaneous speed of all other vehicles. Even with today's ubiquitous communication technology this is not a realistic scenario.
As a result, the control engineering community has considered of interest those decentralized control schemes which use information that can be measured with sensors placed on-board each vehicle, specifically the relative distance from each vehicle to its predecessor in the platoon. This is typically a distance ranging between 20 and 250 yards, which can be measured using a low cost but highly reliable optic (lidar) or radar (electromagnetic) ranging sensor mounted on each vehicle. However, a difficulty dubbed “string instability” has been documented for control schemes with long strings of vehicles that use only local information.
Intuitively “string instability” can be described as the phenomenon of amplification of a disturbance to the leader vehicle, as the disturbance propagates toward the back of the platoon. “String instability” is obviously undesirable, since it can ultimately lead to vehicles in the string crashing into each other. Equally important, lack of a strong attenuation of a disturbance to any car in the string propagating towards the back the string (i.e., a high “sensitivity to disturbances”), even if it does not necessarily lead to instability, it produces another highly unwanted effect: the so-called accordion effect. The accordion effect greatly disrupts the throughput of the highway traffic.
As such, there are a number of challenges and inefficiencies created in traditional automated platooning vehicle design which need to be addressed. Given the technological platforms described above that are already available to the automobile industry, it would be useful to design and implement a feasible control scheme along with suitable control algorithms, in order to tackle the undesired and potentially risky oscillatory phenomena inherent to the dynamics of vehicle platooning (the so-called Forrester effect, or bullwhip effect) while maximizing the throughput of highway traffic by reducing the accordion effect on the behavior of the platoon. It is with respect to these and other problems that embodiments of the present invention have been made.